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isolate from the healthy the sick members of a colony 

 who are the centres of contagion, and all have to be 

 treated together. Further, the bees actively set them- 

 selves to expel all odorous substances as quickly as 

 possible. Again, owing to the nearness in organisation 

 of host and parasite, substances intended to destroy 

 the parasites have a harmful effect on the bee individual, 

 and their use must always be limited as much as 

 possible, to minimise such results. Excitement may 

 arise causing disturbance of the normal routine, such 

 as cessation of breeding, foraging, or any other hive 

 duty. Brood which is passive cannot protect itself ; 

 its health may be affected and loss of such brood in a 

 number of cases results. Continued treatment, unless 

 rnanaged with extreme care and on proved experimental 

 lines, may adversely affect the prosperity of the colony 

 to a material degree, so that although the stock may 

 survive it does not prove profitable as a honey-getting 

 organisation. It may easily happen that a proportion 

 of the adult bees may be killed or rendered useless, and 

 in any case no treatment of this nature will restore the 

 individual sick bees to health. By a curious irony, 



that which the beekeeper has most ardently desired 

 for the last three years, namely some specific which 

 he may introduce amongst the bees to kill mites is 

 the thing which on general principles of bee manage- 

 ment ought not to be done. 



Such treatment must be an urgency measure only. 

 And with the more potent of effective substances, the 

 procedure to be safe must be exact as to quantities 

 and periods of renewal ; casual doses of such substances 

 may prove useless or even disastrous. 



Notwithstanding all this, on account of the undoubted 

 value to the inexpert bee-keeper of having some simple 

 procedure likely to yield even only partial success, in 

 the hope of securing some effective substance with a 

 minimum of harmful qualities and which may be used 

 by a simple procedure, I have persisted with a very 

 large number of experiments including a long list of 

 likely substances. 



Many things capable of destroying the mites when 

 removed from the bees have been found, and no real 



